1. Field of the Invention
The invention relates to a method and an apparatus for transporting a rapidly quenched ribbon from a cooling roll to a winding reel.
2. Related Art Statement
The rapidly quenched ribbon such as an amorphous ribbon is produced by continuously and rapidly quenching molten metal on the surface of a cooling roll rotating at a high speed. Particularly, an amorphous ribbon having a thickness of about 30 .mu.m is produced by rotating the cooling roll at such a high circumferential speed as in a range of 20.about.40 meter/sec.
Accordingly, there has been required a special means for transporting the rapidly quenched ribbon produced at such a high speed from the surface of the cooling roll to a reel.
Japanese Patent Application Laid-Open Publication No. 59-43,772 discloses an ejector type transporting means in the form of a duct having a cavity of a flat rectangular section for blowing out air as a carrier fluid at high speed. The high speed carrier fluid generates a reduced pressure within the duct lower than the atmosphere to suck the atmospheric fluid into the duct and thereby guiding the rapidly quenched ribbon from the surface of the cooling roll into the duct and transporting it to the reel by the carrier fluid. The ejector type transporting means mentioned above can stably peel the ribbon from the surface of the roll and subsequently transport it by the carrier fluid if the atmospheric fluid is not disturbed. The ejector type transporting means has however disadvantages that the suction force by means of an ejector is limited and if the ribbon is clogged in the duct or the ribbon peeling point on the surface of the cooling roll is unstably displaced up and down, the ribbon is broken at the inlet side of the duct.
Japanese Patent Application Laid-open Publication Nos. 56-12,257 and 59-138,572 disclose means for transporting the rapidly quenched ribbon comprising two brush rolls adapted to apply a tension to the ribbon by sliding resistance. There are however disadvantages in that since the rotating speed of the brush rolls is more than 30 meter/sec, the progress of the ribbon is unstable and the ribbon is easily transversely displaced owing to a difference of tension so that it is difficult to continuously transport the ribbon from the surface of the cooling roll. Furthermore, in order to apply an adequate tension, it is necessary to apply a large screw down or pressing force to the upper and lower brush rolls which results in a tendency for a breakdown of the ribbon.
Japanese Utility Model Application Laid-open Publication No. 61-167,248 discloses a ribbon transporting apparatus comprising a pinch roll including upper and lower solid rolls, an air nozzle and a guide conveyor. This transporting apparatus has however no training device and is not adapted to pass the ribbon at high speed. Furthermore, a plurality of tension applicators are sequentially arranged in the outlet side of the cooling roll and result in a large tension at the initial winding so that the ribbon is necessarily broken between the cooling roll and the pinch rolls.
Japanese Patent Application Laid-open Publication No. 59-57,864 and Japanese Patent Application Publication No. 60-48,431 disclose means comprising dancer rolls for winding the ribbon. This winding means has however a drawback such that in order to improve the shape of the wound ribbon rolls it is necessary to apply a large tension, but the cooling roll is directly affected by such a large tension to render the casting unstable.
Furthermore, Japanese Patent Application Publication No. 59-34,467 discloses an approximate magnet reel, but it has a drawback such that since the reel is adjacent to the cooling roll, a measurement and control system cannot be easily arranged so that it is difficult to stably produce the ribbon for industrialization. An inwardly blowing reel disclosed in Japanese Patent Application Laid-open Publication No. 57-3,901 is also difficult to continuously feed the ribbon from the cooling roll.